Chapter 13. Chapter 13: Forests

What is the three-dimensional structure of a forest...?

Why You Should Care

Aldo Leopold, considered a father of modern environmental science wrote, “One of the penalties of an ecological education is that one lives alone in a world of wounds.” By this, he meant that, once you know what you’re looking at out in "nature," you’ll unfortunately realize just how messed up most forests and other natural areas are. The three-dimensional structure of a forest is an indicator of its health. For example, a forest with trees of the same species, all uniformly sized, and little woody vegetation (small trees or shrubs) underneath is probably a human-maintained tree plantation grown for paper pulp or lumber. A forest with densely growing shrubby vegetation has probably been disturbed somehow: Road clearing or lumber removing could open up light gaps to allow dense growth of shrubs; invasion by non-native species that can out compete native species; or the overfragmentation by development.

The three dimensional structure of forests is also important to understand if one is to understand energy flow in forest ecosystems and its impact on climate. Similar in concept to the way inefficient energy transfer means fewer organisms at each trophic level (refer back to Infographic 8.2), incomplete light capture at each level of the forest means less total plant biomass but higher photosynthetic efficiency as you travel down through each layer of the forest. In this way, forest plants are able to capture nearly all of the light energy that reaches them through the atmosphere.